Catalytic side chain oxidation of aromatic compounds



Patented Mar. 29, 1932 UNITED STATES PATENT orrlca ALPH'ONS O. JAEGEB, OI GRAFTON, PENN'SYL'VAliI'IA, ASSIGHOR TO THE BEIIDEN COE- PANY, OF PITTSBURGEJENNSYLVANIA, A CORPORATION OF DELAWARE CATALYTIC SIDE CHAIN O;XIDATION OF ABOMLATIG COMPOUNDS Io Drawing. Original application meal August 8, 1927, Serial No. 211,638. Divided and this application V filed March 30, 1928. Serial No. 288,104.

This invention relates to the catalytic oxidation of the side chains of side chain arochain aromatic compounds are oxidized, preferably in the vapor phase, to the corresponding aldehydes and acids by causing them to react withan oxidizer, for example an oxidizm ing gas such as air, in the presence of a new class of catalysts or contact masses, namely,

catalysts or contact masses which contain nonsilicious base exchange bodies, diluted or undiluted. Some of these new catalysts and contact masses have been described and claimed as products in my application, Serial No. 171,727, filedFebruary 28, 1927, which matured into Patent No. 1,694,620 dated December 11, 1928, of which the present application is in part a continuation. The catalytic oxidation of organic compounds generally by means of catalysts or contact masses containing non-silicious base exchange bodies has been described and claimed broadly in my application, Serial No. 211,638, file August 8, 1927, which matured into Patent No. 1,7 35,- 763 dated November 12, 1929, of which the present application is a division.

The non-silicious base exchange bodies used in the present invention may be produced by the reaction of metallate components with metal salt components under conditions'so that the reaction mixture remains substantially alkaline to litmus. The invention is in no sense restricted to the use of catalysts which are the reaction products of a-single metallate and a single metal salt component, and some of the most effective catalysts for use in the present invention are the reaction products of a plurality of metallate components with one or more metal salt components or a plurality of metal salt components with one or more metallate components.

All of the base exchange bodies used in the present invention, that is to say, catalytically active bodies which are prepared by the reaction of a single metallate with a single metal salt or bodies produced by the reaction of at least one metallate with a plurality of metal salts, or vice versa, possess a remark- -According to the present invention side ably porous, frequently microporous strucf tureand in some cases are opalescent. When suitable catalytically active components are present in the products, they form catalysts of remarkable efliciency due probably to the extraordinarilyhigh surface energy of the microscopically porous structures and probably also to the presence of unsaturated valences in many cases and asymmetry of molecules. It is of course possible that-the catalytic activity of the products is due partly or wholly also to other reasons,and the present invention is not intended in any sense to be limited by any theory of action of the products. The molecular complexes which are present are apparently of great size and complexity, and the exact chemical constitution has not been determined. In fact it is not even definitely determined whether single chemical compounds are formed in any or all cases and it is possible that molecular mixtures are present. The products possess a physical ymicroscopical homogeneity and be have in many ways as if they were single compounds, and I am of the opinion that probably in many cases the products are in fact single compounds of very high molecular weight, but the invention is not limited to any theories of the chemical constitution of the products.

It should be clearly understood that the products used in the present invention are of silicon, which has hitherto been considered as essential to the formation of the skeletons of such advantageous physical structure, ap-

ucts. Surprising as it may seem, the presence pears to be-only one of many elements which I are capable of bringing about these physical pro ertles and many of the base exchange bodies of the present invention possess all of the mechanical strength'and resistance of the silicious zeolites, properties which are of course of utmost importance in, catalytic oxidations of organic compounds.

A number of elements are capable of forming alkali metal metallates, at least in their higher states of oxidation, and can be used singly or in mixtures, as the metallate components for producing base exchange bodies used in the present invention, it being understood of course that the choice will depend on the metal salts to be used and on thecatalytic efiects which it is desired to produce. Among the elements which form metallates are the following :aluminum, chromium, zinc, vanadium, beryllium, tin, palladium, platinum, titanium, zirconium, tungsten, uranium, tantalum, boron and molybdenum. The elements which form the metallates may be present in the form of their oxides or hydroxides united with alkali to form simple metallates, or they I may be present partly or wholly in the form of complex compounds, such as for example, ammonia complexes, cyanogen complexes, and the like. In general, the complex compounds described in the co-pending application of Jaeger & Bertsch, Serial No. 100,116, filed April 19, 1926, may be used.

The metal salt components include the water soluble neutral or acid salts of the following elements :copper, silver, gold, beryllium, zinc, cadmium, aluminum, rare earths, titanium, zirconium, tin, lead, thorium, chromium, uranium, vanadium manganese, iron, nickel, cobalt, platinum, palladium, which may be used alone or in any desired mixture. It isan advantage of the present invention that definite proportions of the individual compounds do not need to be used, either because mixtures .of different compounds are formed, 'or more. probably because the tremendous size and complexity of the molecule masks any requirements for definite proportions.

All of the products used in the present invention possess base exchanging powers to a greater or less extent when first prepared in solutions which are substantially neutral ,or alkaline to phenolphthalein. For the oxidation of side chains, however, high base exchanging power of the products is not required and it is therefore possible to depart considerably from the optimum conditions of production as far as base exchange power goes. In other words, the limits of alkalinity, neutrality or acidity are much wider than in the case of products which are to be used for water softening, and which therefore depend rimarily on their base exchanging power. Vhile usually the highest base exchanging powers are obtained when the compounds are produced in a reaction mixture which is substantially neutral or alkaline to plhenolphthalein products having a similar p ysical structure and being desirable for the catalytic oxidation of organic compounds can be prepared with somewhat different proportions of the components, so that at the end of the reaction the mixture may possess any alkalinity or acidity between phenolphthalein red and litmus blue as indicator end points.

The possibilities of producing catalysts according to the present invention are not limited to the reaction products of the metallates and metal salt components which may be used and which are present in the molecules in a non-exchangeable form. On the contrary, a further series of products can be prepared by exchanging part or all of the alkali cations for other atoms or radicals by means of base exchange. The number of cations which-can be introduced is very large, and some of them are included in the following elements and radicals :ammonium, copper silver, gold, beryllium, magnesium, caesium, zinc, strontium, cadmium, barium, mercury, aluminum, thallium, titanium, zirconium, tin, thorium, vanadium, chromium, uranium, manganese, iron, cobalt, nickel, palladium, platinum. These cations may be introduced either singly or in mixtures, simultaneously or successively. The wide possibilities of combination which can be effected by the introduc tion of various cations by means of base exchange gives the catalytic'chemist an almost infinite field of choice in preparing catalysts having just the right degree of activity for organicoxi-dations and it is an advanta e of the present invention that catalysts 0 exceedingly finely adjusted activity can be produced and are effective. The cations introduced by base exchange may be themselves catalytically active, or they may activate catalytic components which are present in the products in non-exchangeable form. Cations may also be introduced as simple ions or as complex ions. In all cases, the catalytic activity of the roducts obtained is enhanced by the favora le physical structure of the products.

- A further series of products can be ob tained by treating the base exchange bodies used in the present invention either with or without the presence of cations introduced by base exchange, with products containing anions which are capable of reacting with the base exchange body to form salt-like products.

In the contact masses containing salt-like bodies which are used in the present invention the catalytically eflfective components may be present solely in the base exchange body, solely in the anion of the salt-like'body, or partly in one and partly in the other.

Acid radicals of the following elements,-

either simple acids polyacids or complex anions, can be used in producing salt-like bodies with the base exchange bodies of the present invention :vanadium, tungsten, uranium, chromium, molybdenum, man

muth, sulfur,

ganese, tantalum arsenic, phosphorus, bishlorine, platinum boron. Complex ions, such as for example, term and ferricyanogen, sulfocyanogen, metal cyanogen, and the like may also be used wherever they form salt-1i 'e bodies with the. base exchange bodies of the present invention. A single acid radical may be introduced, or a mixture may be used, either by a simultane-" ousor successive treatment. The amount of the acid radical used may also be varied so that the products may possess the character of acid, neutral or basic salts.

While it is possible to use certain of'the catalysts of the present invention in an undiluted form, best results are usually obtained by the dilution of the products with more or less inert bodies, or with bodies of relatively feeble catalytic powers or activating powers. Diluents can be incorporated with the catalytically active base exchange body before or after formation, and are preferably although not necessarily, incorporated therewithto produce a physically homogeneous structure. In addition to finely divided carriers, diluted or undiluted catalyically active base exchange bodies can be coated on or impregnated in relatively massive carrier fra ments, the incorporation taking place be ore, during or after formation of the base exchange body. It should be understood of course inall cases that where a perfectly homogeneous product is desired, the incorporation of diluents must take place before the base exchange body after formation has set. Practically all of the base exchange bodies used in the present invention are first formed as gels, in which condition they can be incorporated with diluents or carrier bodies but after once setting, and particularly after drying, it is of course impossible to incorporate diluents into the base exchange bodyother than. by purely physical mixture, which in general is less desirable, but which is not excluded from the broader aspects of the present invention.

7 A large number of diluent bodies can be used, such as silicious materials, as kieselguhrs of all kinds, diatomite brick refuse, pumice meal, pulverized quartz, sand, and other minerals, especially those rich in silica. In the same way, a large' number of natural or artificial massive carrier fragments can be used, such as fragments of pumice,diatomite bricks or other minerals, metal granules and the like. In general, the methods of incorporation and many of the diluents which can be used are described in the co-pending application of J aeger and Bertsch, Serial No. 95,771,fi1ed March 18, 1926. I

The high porosity of the products which are prepared may be even further increased by incorporating into the framework of the base exchange body products which can be removed by leaching, volatilization or com- K i bustion, and which when removed leave additional porous spaces and produce an even more advantageous physical structure. The

substances added may be of organic or inorgamc nature and may be added as individuals or may be in chemical combination with some of the permanent components. Thus for example, certain of the components may be introduced in the form of complex compounds which are later decomposed and then leave additional porous spaces. Examples of such compounds are certain ammonia complexes which can .be decomposed by heating the finished, product. c

In general, the reaction of the component solutions results in the production of soluble salts which are not wanted, and it is therefore usually desirable to wash the base exchange body, after precipitation and then to 'dry, or dry first and then wash. '1 have found that while it is possible in some cases to dry at high temperature, for the best results, in most cases drying temperatures of 100 (3., or less, are desirable.

In the general methods described above, separately prepared metallate components and metal salt components have been caused to react. While for many purposes these are the preferred methods, it is possible to prepare base exchange bodies by somewhat different methods. Thus for example, if a solution of a metallate of amphoteric metal is cautiously neutralized with acid, until the strongly alkaline reaction becomes weakly alkaline to phenolphthalein, or even slightly acid with weak alkalinity to litmus, as a limit, base exchange bodies are produced, and in many cases are of importance, particularly for certain side chain oxidation processes. Instead of the metallates, the amphoteric metals may also be present in the form of complex metallate compounds, for example, such complex compounds as are described in the co-pending application of J aegcr & Bertsch, referred to above.

In a similar manner, acid or neutral solutions of salts of amphoteric metals may be treated with alkali until the mixture becomes neutral or alkaline to phenolphthalein, or even acid, in which case base exchange bodies are produced in a manner similar to that described in the foregoing paragraph. The base exchange bodies produced either by neutralizing metallate solutions or metal salt solutions in general do not show quite as great base exchange power as do those which are prepared ,by causing ready made metallate and metal salt solutions to react with each other. The physical structure, however, appears to be similar and, as in many cases, particularly in certain side chain oxidation processes, extremely hlgh base exchange power is not essential. Many very valuable v catalysts can be produced in this manner.

A further wet preparation consists in causing alkali metal salts of the oxygen-containing acids of metal elements of the fifth and sixth group of the periodic system, such as for example, vanadium, molybdenum, tantalum, tungsten, and the like, to react .with neutral or acid salts of metals, particularl Y metals which are strongly amphoteric. Pre erably there should be an excess of alkali. The salts of the fifth and sixth group acids may be used alone or in combination with other metallates.

In addition to the wet methods, which for most purposes I find are preferable, base exchange bodies can be produced by fusion methods, for example, by fusing oxides or hydroxides of the metallate and metal salt components with-alkali such as, sodium carbonate or potassium carbonate or their h droxides. The base exchange bodies produced by fusion, while sometimes they do not possess quite as high base exchange powers, are nevertheless of a similar advantageous physical structure, and, many of the products are very valuable catalysts. Oxides of the metals of the fifth and sixth groups may also be used to form products somewhat similar to those described in the preceding paragraph by fusion methods.

The non-silicious base exchange catalysts described above contain the catalytically active element or elements in chemical combination with the base exchange body or forming part thereof, and they are among the most effective catalysts used in the present invention. It is not necessary, however, that the catalyticactivity should reside in the base exchange body itself, and many very important catalysts can be produced in which catalytically inactive base exchange bodies are united with catalytically active di1uents to form physically homogeneous masses. These masses, although they do not contain catalytic elements chemically combined with the base exchange body, of course share its microporous structure, and where suitable catalytically active diluents are used, catalysts of great efiiciency are obtained, and are included in the scope of the present invention. Of course the catalytic activity may reside both in the diluents and in the base exchange body.

The catalysts used in the present invention, and particularly diluted catalysts, may in many cases with advantage be given a preliminary treatment consisting in a calcination and exposure to oxidizing or acid-vapors at an elevated temperature as described in In prior Patents Nos. 1,678,626 and 1,678,627 dated July 24, 1928.. Such treatments frequently produce secondary chemical changes as are produced in the catalyses themselves, and it should be understood that the catalysts of the present invention are defined asusual methods of definition in catalytic chemmany aromatic compounds, require a slowing down, or stabilizing, of the catalysts used, in order to prevent excessive losses through total combustion, or to permit stopping at a definite intermediate oxidation product with maximum yield. I have found that the presence of salts of alkali-forming metals and other non-catalytic components may act as stabilizers, as may the oxides or hydroxides themselves in some reactions. Other catalytically active or activating substances which are not specific catalysts for the oxidation of side chain aromatic compounds which enhance the effectiveness of the stabilizers, and which are termed stabilizer promoters, may also be used. In fact, whenever base exchange catalysts of the present invention which contain exchangeable alkali metal cations are given preliminary treatment with acid Vapors, alkali forming metal compounds are produced which act as stabilizers and many of the amphoteric or other metal components which are not selective catalysts for the particular oxidation reaction may be considered, and act as stabilizer promoters. I do not claim in this application the use of stabilizers or stabilizer promoters in general, as these form the subject-matter of my copending application, Serial No. 265,521 filed March 28, 1928. The expressions stabilizers and stabilizer promoters, when used in the present application, are to be understood as used in the sense in which they are defined in the afore-mentioned co-pending application. It should be understood that while many of the base exchange catalysts used in the present invention may be considered as composite stabilizers and stabilizer promoters, the invention is not limited thereto, and stabilizers or stabilizer promoters, or both, may be separately added to the catalysts of the present invention, and in fact many of the diluents, for example those containing certain heavy or amphoteric metal compounds, are to be considered as stabilizer promoters.

The invention will be described in greater detail in connection with the following specific examples which are illustrative merely, and do not limit the broader scope of the invention. The examples, however, do in many 3 cases contain specific features Which in their more narrow aspects are included in the present invention. The examples give a few typical reaction conditions and catalysts, but it should be understood that the skilled catalytic chemist will choose within the confines of the present invention catalysts and reaction conditions best suited to the particular installation in which he is interested.

meanest 40 parts of VJ), are nded in=500 parts Adiluted or undiluted potassium vanadyl of water and acidified wlth a little concentrated sulfuric acid. The suspension is heated almost to the boiling point and gases containing SO, are passed through untll the vanadic acid suspension is comsgletely dissolved as blue vanadyl sulfate. 7 metimes it is necessary to add some water in order to get the vanadyl sulfate entirely dissolvedw The solution is then divided into two parts, one of which is set aside and the other treated withfi N. otassium hydroxide solution at o60 until a clear cofiee brown solution of tassium vanadite is obtained. The vana 'te solution is mixed with 70 parts of small diatomite brick fragments or 40 parts of Celite and 40 parts of quartz articles, the mixture being stirred until it comes uniform. Other diluent bodies-such as neutral silicates, sand, silica gel, ground rocks, tuifs, lava of volcanic or eruptive origm, or similar materials may be used. To

the solution containing potassium vanadite the second half of the vanadyl sulfate solution is added, care'being taken that even after all of the vanadyl sulfate has been added, the solution remains alkaline or neutral to phenolphthalein. The reaction product, after separation from the mother 1i nor by filtration and drying at 60 to 70 is broken into fragments and constitutes a base exchange body containing otassium and tetravalent vanadium, part 0 thevanadium playin the part of an acid radical and part that o a base in the non-exchangeable portion of the molecule.

The product obtained is well suited for the catalytic oxidation of toluol to benzal dehyde, chlortoluols, dichlortoluols', chlorbromtoluols, nitro-toluols, chlornitro-toluols, brom-nitro-toluols and the like, to the correspending substituted benzaldehydes, the vapors of the compounds, mixed with air in the proportion of 1:15 to 1:30 bein passed over the catalyst at temperatures 0 320 to Example 2 the acids predominating, the vapors of the.

compounds being mixed with air in the'proportion of 1-20 and passed over the catalyst at temperatures of 360 to 450 C. a

can also be preparedd diluted or undiluted zeolites, metals such as aluminum granules, metal alloys, ferro sili con, ferro-vanadium ferro-c'hrome and the like, particularly w ere their surface has been roughened.

The coating can be either after formation of the product or the roduct can be caused to react on the carrier ragments and be generated in situ. Artificial carrier fragments for example, by formelite, kieselguhr, puling fragments of verized" silica gel and silicates, highly ab-' sorptive glaucosil which is the siliceous residue from the aci extraction of green sand, diluted or undiluted. zeolites, using various adhesives, such as waterglass, alkalies and alkali metal salts'followed, after action by calcination at 400 to 500 C. and if necessary treatment with acids.

When the base exchange body or its saltlike body is coated onto the carrier fragments, as enumerated above, afterit has been formed, various adhesives can be used which may be stabilizers or stabilizer promoters for the catalyst. Thus, for example, many acid, alkaline and neutral salts of the alkaliforming metals such as sulfates, chlorides,

nitrates, nitrites, waterglass, carbonates, hy-

droxides and the like can be used.

Instead of introducing diluent bodies into the base exchange body during formation, as described in the foregoing examples, the undiluted base exchange body can be prepared from its components potassium vanadite and vanadyl sulfate, and then mixed mechanically in aqueous suspensions with the diluent bodies or the base exchange body maybe dried and pulverized and then mixed with the latter. For example, 50 parts of Celite Brick particles may be used and the mixture formed into granules with any of the above described adhesives. A very efficient catalyst is thus produced for the catalytic oxidation of xylenes, mesitylene, pseudocumene and para cymene to the corresponding aldehydes and acids, the vapors of the compounds being mixed with air in the proportion of about 1-20 and passed over the calcined catalyst at tem peratures of 340 to 420 C.

Example 4 Base exchange bodies are prepared by using potassium tungstate, potassium chromate, potassium molybdate or potassium tantalate molecularly-equivalent amounts instead of ion potassium vanadate hs in Example 6. These catalysts especially after preliminary treatment with urner gases diluted with? air at 450500 C. are well suited for the oxidation 5 of toluol to benzaldehyde and benzoic acid I,

for the catalytic oxidation of toluol and itsv and substituted toluols to thecorrespon'ding aldehydes and acids when the vapors of these products, mixed with .air in the proportion of 1:35 by weight, are-passed'over the contact masses at 340390 C. V

Ewample5 v A vanadyl base exchange body is prepared by suspending 20 parts of V 0 in 500 parts of water, adding a little concentrated sulfuric acid and then reducing the V 0 with gases containing sulfur dioxide at the boiling point until it is completely transformed into blue vanadyl sulfate. The vanadyl sulfate solution is then divided into two parts, half of which is treated at 5060 C. with suflicient 5 N. KOH to form a clear coffee-brown solution of potassium vanadite, to which 50 parts of Celite earth is added as a diluent. The second half of the original solution is then added with vigorous agitation, care being taken that the alkalinity remains between phenolphthalein red and litmus blue. The gelatinous product is sucked but not dried and constitutes a vanadyl base exchange body. 10.2 parts of freshly precipitated aluminum oxide are brought into solution with parts of 100% KOH in 200 parts of water. The 'vanadyl base exchange body described above is then stirred into thesolution and a 10% aqueous solution containing 37 parts of ferric sulfate with 9 mols of water or 44.4 parts of aluminum sulfate with 18 mols of water or a mixture of the two, is added to the aluminate 40 mixture with vigorous agitation. The reac tion product produced, which is an aluminum iron base exchange body and which does not possess efiective catalytic properties for the catalytic oxidation of most organic compounds, is diluted with the catalytic-ally active vanadyl base exchange body and is thereby transformed into a highly active catalyst for the above referred to processes. The reaction product is sucked, pressed, washed with 300-400 parts of water, dried and broken into fragments. The fragments may be treated with 5% copper sulfate,silver nitrate,cobalt nitrate or iron nitrate solutions to partly replace the alkali with these metals. The product may also be treated with salts of the metal oxygen acids of the fifth and sixth groups, preferably with a 1% ammonium vanadate solution, resulting in a so-called salt-like body after the soluble components have been washed out.

. The products are calcined with air or gases containing carbon dioxide at 400 C. the calcination temperature being permitted to rise gradually in order to prevent undesirable changes in the structure of the base exchange iihkifsm body. After this preliminary calcination the product may -be preferably treated with 3-5 burner gases at 450 C. and is then ready for use.

The contact mass so obtained is well suited substitution products to the corresponding- --benzaldeh'ydes or benzoic acids. The vapors of the organic compounds, mixed with an or other oxygen contalning gases, such as, for

1 example, CO and oxygen, in the proportion of from 1 :20 to 1: 30 are passed over the catalyst at 350420 C.

In this example the aluminum iron base exchange body may be considered as a complex stabilizer for the catalyst in these reactions. In order to promote or tune the stabilizing action of the catalyst various stabilizer promoters can be added in the form of silicates or heavy metal oxides such as fer- 'ric oxide, copper oxide, titanium 'dioxide, manganese dioxide, zirconium dioxide, cerium dioxide, beryllium oxide, calcium oxide, cobalt oxide or thorium dioxide. They may be added singly or in mixtures and may advantageously be formed in a nascent state. The amount of the stabilizer promoter added depends on the effect desired; in general from 25% of such stabilizer promoters gives good results. These stabilizer promoters of course, may be added in the same manner as any other diluent as has been generally described in the introductory portion of this application.

A different method of introducing the stabilizer promoters consists in replacing part or all of the metal salt components of the base exchange body with correspondingamounts of beryllium sulfate, silver nitrate, nickel sulfate, cadmium sulfate or similar mineral acid salts of these bases.

In many cases it is desirable to neutralize excess alkali in the reaction products with 5% mineral acid such as hydrochloric acid, sulfuric acid, nitric acid or the like until the alkalinity has been brought to the desired point. ,Other catalytically active base exchange bodies, may, of course, be introduced as diluents instead of the one described.

Ez vample 6 8 parts of V 0 and 5.1 parts WC) are dissolved in a 2 N. KOH solution containing 26 C. and then broken in small pieces suitable 0 for catalysis. After drying it may be desirable sometimes to trickle .water over the broken fragments in order to wash out the exges; of salts formed in the preparation of this The dried diluted base exchanging bodycontaining V 0 W0; and A1 0 1n non-exchangeable form is advantageously treated at 420 to 500? C. with gases containing S0 and oxygen in strong dilution and then is blown air. The contact mass so obtained is well suited for the catalytic oxidation of cresol to salicylaldehyde and salicylic acid; when the compounds mixed with air in the ratio of i 1 25 by weight and the mlxture is passed over a I Ea'ample '7 6.7 parts of freshly precipitated A1 0 are mixed'with 12 partsof V 0 and suificient crystallized oxalic acid or other reducing agents, such as powdered carbon, are added in order to reduce the V20 in the process to V 0 11 parts of 100% KOH or 13 parts of K CO are thoroughly mixed with the other components. The entire mixture is then heated up .to the sintering point or to incipient melting. The melted mass is crushed to small pieces and leached with water in order to remove excessive alkali. The catalytically active base exchange body so obtained is ground and then embedded in a catalytically inactive zeolite body as follows:

90 parts of 33 B. waterglass are diluted with 5 to 10 volumes of water and the base exchange body obtained, as described above,

- is obtained almost at once and is increased lit together with '80 parts of infusorial earth are added with vigorous stirring, in order to obtain a good distribution. parts of aluminum sulfate. with 18 mols of water are dissolved in 200 parts of water and sufficient 10 N. potassium hydroxide solution isadded to dissolve up the aluminum hydroxide which is at first precipitated, forming a potassium aluminate solution. a

The aluminate solution is then stirred into the suspension and the mixture heated up to about 60 to C. A gelatinous precipitate by the gradual addition of 2 N. sulfuric ac d. Care should be taken, however, that alkalinity to litmus or neutrality to phenolphthalein is maintained. The stirring is continued for an hour, during which time the mixture is gradually permitted to cool down to room temperature. The gelatinous precipitate obtained is pressed and washed with 200 parts of water in small rtions. The filter cake is then dried and 'roken into fragments of suitable size. careful calcination for urposes of'dehydration, constitutes an eficient contact mass, for the catalytic oxidation of organic com ounds such as toluol to benzaldehyde and acid whentoluol va ors mixed with air in the contact mass at 360 to 380 C. It is sometimes advantageous to add superheated steam to the gaseousreactionmixture before pass a 'in over the contact mass.

11 most of the examples the metal salt so- I lution is added to the metallate solution, and

The mass so obtained after.

nzoic ration of 1:25 weight are passed over the this maybe considered as the preferred method for producing nonsilicious base exchange bodies used as contact masses in the present invention, but it should be understood that the invention is not limited to the use of contact masses or catal sts roduced by this preferred procedure. n t e contrary, some valuableyc'ontact masses may be produced by the converse procedure, in which the metallate solution is added to the metal salt solution. As in this case the relatively alkaline solution ise added to the relatively acid solution it is impossible to maintain continuously an alkaline reaction. Care must of course be taken that in all cases after the reaction is completed the mixture shows alkalinity to litmus, and preferably a. neutralityor alkalinity to phenolphthalein.

' What is claimed as new is:

1. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the compounds to react with an oxidizing gas in the presence of a contact mass. containing a non-silicious base exchange body. v 2. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to react in the presence of a contact mass containing a non-silicious base exchange body.

3. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxldizing gas to react in the presence of a contact mass containing a diluted non-silicious base exchange body.

4. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of thecompounds admixed with an oxidizing gas to react in the presence of a contact mass containing a nonsilicious base exchange body, at least one catalytically active component of the contact mass being chemically combined in or with the non-silicious base exchange body.

5. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to react in A the presence of a contact mass containing a non-silicious-base exchange body, at least one pounds admixed with an oxidizing gas to react in the presence of a contact mass containing a diluted non-silicious baseexchange body, at least one catalytically eflective component of the contact mass being physically associated with the non-silicious base exchange body in the form of a diluent.

7. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the com-- pounds admixed with an oxidizing'gas to react in the presence of a contact mass containing a non-silicious base exchange body, the contact mass also containing at least one compound of an element included within the group alkali metals, alkaline earth metals.

8. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to re act in the presence of a contact mass containing a non-silicious base exchange body, the contact mass also containing at least one compound of an element included within the group alkali metals, alkaline earth metals and at least one catalyst included in the group consisting of hydrogenation catalysts, dehydrogenation catalysts, reduction catalysts, oxidation catalysts which, when used alone, are not specific catalysts for the oxidation of side chain aromatic compounds.

9. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to react in the presence of a contact mass containing a non-silicious base exchange body, the contact mass also containing at least one compound of an element included within the group alkali metals, alkaline earth metals chemically combined in the non-silicious base exchange body. v

10. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to react in the presence of a contact mass containing a non-silicious'base exchange body, the contact mass also containing at least one com pound of an element included within the group alkali metals, alkaline earth metals and at least one catalyst included in the group consisting of hydrogenation catalysts, dehydrogenation catalysts, reduction catalysts,

are notspecific catalystsfor the oxidation of v side chaln aromatic compounds chemically combined in or with the non-silicious base exchange body.

11. A method of oxidizing the side chains of side chain aromatic compounds, which comprises causing the vapors of the compounds admixed with an oxidizing gas to react in the presence of a contact mass containing a. non-silicious base exchange body, the contact mass containing an oxycompound of vanadium as at least one of its catalytical ly active components.

12. A methodl-of oxidizing the side chains of side chain aromatic compounds, which comprises'jcausing the vapors of the compounds admixed with an oxidizing gas to react in the presence of a contact mass containing anon-silicious base exchange body in which chemically combined vanadium is present.

13. method of oxidizing the side chains of benzene homologue compounds, which comprises subjecting them to reaction with an oxldizing gas in the presence of a contact amass containing a non-silicious base exchange 14. A method of oxidizing the side chains of benzene homologue compounds, which comprises causing-i'the vapors of the compounds to react with an oxidizing gas in the presence of a contact mass containing a nonsilicious base exchange body.

15. A method ofoxidizing the methyl group of benzene homologue compounds containing at least one methyl group, which comprlses causing the compounds to ,react with'an oxidizinggas in the presence of a catalyst containing a non-silicious base exchange body.

16. A method of oxidizing the methyl groups of benzene homologue compounds containing at least one methyl group, which comprises causing the vapors of the compounds to react with an oxidizing gas in the presence of a contact mass containing a nonsilicious base exchange body.

17. A method of oxidizing the side chains of toluene compounds which comprises causing the compounds to react with an oxidizing gas in the presence of a catalyst containing a non-silicious base exchange body.

18. A method of oxidizing the side chain of toluene compounds, whichcomprises causing the vapors of the toluene compounds admixed with an oxidizing gas to react in the presence of a contact mass containing a nonsilicious base exchange body.

19. A method of oxidizing the side chain of toluene, which comprises causing toluene to react with an oxidizing gas in the presence of a catalyst containing a non-silicious base exchange body.

20. A method of oxidizing the side chain of toluene, which comprises causing the vapors of toluene admixed with an oxidizing gas to react in the presence of acontact mass gonitaining a non-silicious base exchange Signed at Pittsburgh, Pennsylvania, this 23rd day of March, 1928.

-ALPHONS O. JAEGER. 

